Needle-tip electrocautery versus steel scalpel incision in neurosurgery: study protocol for a prospective single-centre randomised controlled double-blind trial

Abstract

Introduction

Electrocautery is used widely in surgical procedures, but making skin incision has routinely been performed with scalpel rather than electrocautery, for fear that electrocautery may cause poor incision healing, excessive scarring and increased wound complication rates. More and more studies on general surgery support the use of electrocautery for skin incision, but research comparing the two modalities for scalp incision in neurosurgery remains inadequate. This trial aims to evaluate the safety and efficacy of needle-tip monopolar for scalp incision in supratentorial neurosurgery compared with steel scalpel.

Methods and analysis

In this prospective, randomised, double-blind trial, 120 eligible patients who are planned to undergo supratentorial neurosurgery will be enrolled. Patients will be randomly assigned to two groups. In controlled group scalp incision will be made with a scalpel from the epidermis to the galea aponeurotica, while in intervention group scalp will be first incised with a steel scalpel from the epidermis to the dermis, and then the subcutaneous tissue and galea aponeurotica will be incised with needle-tip monopolar on cutting mode. The primary outcomes are scar score (at 90 days). The secondary outcomes include incision pain (at 1 day, on discharge, at 90 days) and alopecia around the incision (at 90 days), incision blood loss and incision-related operation time (during operation), incision infection and incision healing (on discharge, at 2 weeks, 90 days).

Ethics and dissemination

This trial will be performed according to the principles of Declaration of Helsinki and good clinical practice guidelines. This study has been validated by the ethics committee of West China Hospital. Informed consent will be obtained from each included patient and/or their designated representative. Final results from this trial will be promulgated through publications.

Trial registration number

ChiCTR2200063243.

Strengths and limitations of this study.

• This study is a prospective, single-centre, randomised, controlled, double-blind trial about safety and efficacy of needle-tip monopolar for scalp incision.

• This study is comprehensively conducted to identify differences between these two modalities using a variety of clinical relevant outcomes.

• Our limitation is that we only and strictly recruit patients undergoing supratentorial neurosurgery with a single incision without history of previous neurosurgical craniotomy.

• This trial might be underpowered to ascertain the difference between the two groups because sample size is calculated based on an assumed effect size.

Introduction

The use of electrocautery dates back to 1909 for removal of tumours.¹ Later William T. Bovie invented the first commercial electrocautery device, which was first used clinically in brain tumour resection by neurosurgeon Dr Harvey Cushing in 1926.² Thereafter, the electrocautery equipment was gradually improved, resulting in the more commonly used monopolar electrocautery and bipolar electrocautery.

Although electrocautery has the advantages of less bleeding, faster speed, complete haemostasis and less sharp injury to operators,^3–8 it is currently mainly reserved for incision and separation of subcutaneous tissue and deeper layers as well as haemostasis, while rarely used by surgeons to cut skin for fear that the heat generated by electrocautery may damage the skin tissue and appendages around the incision, resulting in poor incision healing, excessive scarring and devitalised tissue may also become a focus of infection.^{9 10} Nonetheless, scalpels have other inherent disadvantages, including unclear anatomical hierarchy due to bleeding wounds, the need to ligate blood vessels with sutures, leaving sutures as foreign bodies remaining in the body which may lead to wound infection or foreign body reactions, sharp injuries which may lead to infection of blood-borne infectious diseases and unintentionally damaging surrounding vital organs and structures during procedures.^{11 12} On the other hand, there has been some literature on abdominal incisions showing that there is no statistical difference in postoperative complications between incisions made with conventional scalpel and electrocautery.4–7 13–16 In terms of incision scar cosmesis, Stupart et al compared the effects of monopolar electrosurgery and scalpel on incision scars in abdominal surgery and found no statistical difference between the two groups.¹⁷ In a randomised controlled trial, Aird et al used the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Assessment Scale (POSAS) to quantitatively compare the aesthetic differences between the incisions formed by the two methods, and the conclusion was similar to that of Stupart et al.¹⁸ Meanwhile, Aird et al reported similar incision infection rate between the two groups and significantly lower postoperative incision pain in the electrocautery group on the first day after surgery.¹⁸ Several other studies have found that incising skin by electrocautery with cutting modality during abdominal, chest, upper extremity and neck surgery reduces incision time, blood loss^3–7 and acute postoperative pain.^{5–7 15}

Scarce research has been done concerning the effect of cutting methods on skin incision in neurosurgery. Most of the existing studies on head and neck cancer, craniofacial surgery and neurosurgery have shown no statistically significant difference in the incidence of postoperative wound infection and dehiscence between electrocautery and scalpels.3 10 11 19 This is especially important for the scalp, as poor wound healing often results in hypertrophic scarring and baldness around the incision, seriously affecting the patient’s aesthetic satisfaction. Several more sophisticated, thinner-tip electrocautery devices have appeared, such as needle-tip monopolar and microdissection needles. These devices reduce peri-incisional tissue damage by delivering electrical current through extremely sharp tips to a smaller area of skin than conventional blade-tip electrocautery does. Although Papay et al’s study of bicoronal incisions in 12 patients with craniosynostosis indicated that the microdissection needle group had larger scars than the scalpel group (p<0.05),¹⁰ other subsequent studies did not find there was a significant difference in scar formation between microdissection needle and scalpel.¹⁹ Sharma evaluated the effect of microdissection needle on 117 incisions undergoing craniomaxillofacial surgery (including 10 scalp incisions) and found no increased risk of postoperative incision infection or alopecia rates.¹⁹ Similar to what was reported in the study of abdominal incisions, Sheikh’s study of 177 skin incisions for neurosurgical procedures (including 85 cranial incisions) revealed that microdissection needle significantly decreased incision blood loss and incision time compared with scalpel, and no evident alopecia was found around scalp incisions, which made him recommend the use of microneedle electrocautery for all neurosurgery procedures, particularly paediatric cases.³ These studies provided some clues for the application of electrocautery in scalp incision. However, there are still some questions that need to be clearly clarified, including the postoperative scar, incision infection, incision pain and baldness around the incision.

This study intends to comprehensively compare the effect and complications of needle-tip monopolar and steel scalpel for scalp incision in supratentorial neurosurgery through a clinical randomised controlled trial.

Methods and analysis

Patient and public involvement

Patients are not directly involved in the design, recruitment or conduct of the study.

Design

This study is a prospective, single-centre, randomised, controlled, double-blind trial. Figure 1 illustrates the flow chart of the study. This trial will be carried out at the department of neurosurgery in West China Hospital, Sichuan University.

Figure 1.

Trial flow chart.

Patient population: inclusion and exclusion criteria

Patients will be considered eligible if they meet all of the following inclusion criteria:

1. Age ≥18 years old.

2. Patient will receive neurosurgical supratentorial craniotomy with a single incision.

3. The patients consent to receive long-term follow-up.

4. Patient or their legally authorised representative has provided written informed consent.

The following patients will be excluded:

1. Patient suffering from diseases that affect wound healing, such as poorly controlled diabetes, scarring constitution, severe infection, multiple organ failure.

2. History of previous neurosurgical craniotomy.

3. Patient has baldness.

4. Patient has been included in other clinical studies, and the intervention measures will affect the results of the present study.

5. Other circumstances that the investigator considers inappropriate to participate in this clinical trial.

Randomisation

In this study, a simple random method is used. A random number table is generated by a computer, and serially coded opaque envelopes are used to store the random grouping barcode. All eligible patients will be randomly allocated to either needle-tip monopolar group (intervention group) or steel scalpel group (control group). The patient and the follow-up evaluator are blinded to the type of modality used to make the incision. The incision blood loss, incision length and incision-related operation time are recorded by one of the assistants of the operating surgeons and the information is conveyed to the follow-up evaluator without revealing the group of the patient. Once the final statistical analyses have been completed, the randomisation sequence will be disclosed.

Intervention

In addition to the incision modality, the surgical treatment plan is formulated by the doctor based on the comprehensive consideration of the patient’s condition and the wishes of the patient’s family. In scalpel group the patients are incised from the epidermis to the galea aponeurotica with a steel scalpel, while the patients in needle-tip monopolar group are first incised with a steel scalpel from the epidermis to the dermis, and then the subcutaneous tissue layer and galea aponeurotica are incised with a needle-tip monopolar on cutting mode. In both groups bipolar can be used with coagulation mode for haemostasis of bleeding vessels if necessary. After opening the galea aponeurotica, diathermy is used in the desired mode as needed to carry out the complete operative procedure. During the operation the incision length will be measured by using a sterile flexible ruler in centimetres.

Primary outcomes

Scar score (at 90 days): the POSAS and VSS will be used to assess the appearance of the wound at 90 days after surgery.

Secondary outcomes

1. Incision pain (at 1 day, on discharge, at 90 days): Assessed using visual analogue scales.

2. Incision blood loss (intraoperative collection): The gauze exclusively used during making incision, incision suture and haemostasis is weighed by an electronic scale with an accuracy of 1 g. The mass of the sterile gauze is calculated both before and after use. The difference in mass per 1 g is counted as 1 mL of blood. No suction is used during incision and suturing. Blood loss is calculated in millilitre.

3. Incision-related operation time (intraoperative collection): From the skin incision to the complete opening of the galea aponeurotica, including complete haemostasis and the time used for suturing.

4. Incision infection (on discharge, at 2 weeks, 90 days): involving the skin or subcutaneous tissue of the incision and having at least one of: purulent drainage, positive culture, signs or symptoms of infection or diagnosis by a physician.²⁰

5. Incision healing (on discharge, at 2 weeks, 90 days): Poor healing is defined as incision dehiscence and the need for re-suturing. Wound healing disorders will also be recorded.

6. Alopecia around the incision (at 90 days): The follow-up evaluator will ask the patient whether he/she feels alopecia. If the patient can not answer the question, the evaluator will ask the patient’s caregiver.

Duration of surgery and preoperative and postoperative haemoglobin values are gathered as baseline data.

We will provide periodic communications via phone to remind participants of the upcoming visit, as well as to acknowledge their support, to complete follow-up as fully as possible.

Data safety and monitoring board

This study will be carried out as per the principles of Declaration of Helsinki and good clinical practice guidelines. Non-blinded reviews of all patients’ efficacy and safety data will independently be undertaken by an independent data safety and monitoring board (DSMB) comprised of physicians and neurosurgeons. The DSMB will call a meeting at least every 6 months and an interim analysis conference will be conducted when half cases have finished 90 days follow-up. All data will be entered electronically by one clerk and examined by another and stored securely at West China Hospital where the data originated.

In our study an adverse event (AE) will be defined as incision-related undesired medical events that occur in subjects, such as incision infections. Serious AEs (SAEs) include persistent poor healing or suppuration of incision, requiring debridement and death. AEs and SAEs will be collected after the subject has provided informed consent and enrolled in the study. All AEs occurring after receiving intervention and until follow-up completed will be recorded. All AEs and SAEs should be reported to the DSMB.

Sample size estimates

No previous study has investigated the quantitative difference in incisional scarring between needle-tip monopolar and scalpel in neurosurgery. Based on the results of Okereke et al in laparotomy for uncomplicated appendicitis,²¹ the non-inferiority test was used to presuppose the mean 90-day postoperative incision POSAS score cut-off between the needle-tip monopolar group and the steel scalpel group was 1/2 SD of the control group in Okereke et al’s study, that is, 6.58, and the ratio of the number of samples in the two groups was 1. Assuming $\mathrm{\alpha }$=0.05, β=0.20, it was calculated that each group needed 55 patients. Considering the dropout rate of 10%, the sample size was calculated to be 60 in each group.

Statistical analyses

The distribution of data on qualitative variables such as gender and comorbid conditions will be presented as frequency or percentage and be compared between the two groups using χ² test. Continuous variables like age, incision-related operation time, incision blood loss, incision length, incision pain and scar score will be compared between the groups by using independent Student’s t-test or Wilcoxon rank-sum test. Incision infection, incision healing and alopecia around the incision will be compared between the two groups using χ² test.

Discussion

The utility of the steel scalpel or the electrocautery for skin incision is a conundrum, residing in the conflict between excellent incision healing by the scalpel and satisfactory haemostasis by the electrocautery. Although most surgeons are reluctant to choose electrocautery to open skin due to the belief that thermal energy generated from the blade can devitalise the edge of incision and deeper tissues, resulting in wound prone to infection,²² excessive scarring and poor healing, a number of research investigating general surgery has been done demonstrating that diathermy is not only lower in incision time, incision blood loss but also comparable to scalpel with regard to incision infection, cosmesis and dehiscence.4–7 13–18 23

Fast making incision with haemostatic facility is even more important in neurosurgery, especially for scalp incision and paediatric cases in that children have limited total blood volume and incision oozing blood continuously over a long procedure may lead to haemodynamic instability. In spite of the fact that evidence on electrocautery incision versus scalpel incision for scalp opening in neurosurgery is inadequate, existing studies mainly provides promising results, elucidating that there was no significant differences in wound complication rates between incisions created by electrocautery and steel scalpel for head and neck surgery.3 10 11 19 Contrary to others, Papay et al admitted that there was not a difference in wound complications between the two modalities, but revealed a statistically significant wider scar in patients undergoing bicoronal incisions using microdissection needle versus the scalpel.¹⁰ Considering the small final sample size (12 patients completing the follow-up necessary for study inclusion) of Papay et al’s study and subsequent other research which favours electrocautery,^{3 11 19} we incline to the latter and we conduct a prospective, single-centre, randomised, controlled, double-blind trial exclusively in supratentorial neurosurgery to further confirm it.

Our study still has some demerits. First, we aim at patients undergoing supratentorial neurosurgery with a single incision without history of previous neurosurgical craniotomy. These rigorous inclusion criteria might place a restriction on the generalisation of our findings. Second, the sample size in this trial is calculated based on an assumed effect size. Accordingly, it is possible that this trial might be underpowered to ascertain the difference between the needle-tip monopolar and the scalpel group in incisional POSAS scores at postoperative 90 days. Notwithstanding, we believe a well-designed trial could also assist us to better comprehend the properties of needle-tip monopolar.

Ethics and dissemination

This study has been validated by the ethics committee of West China Hospital, and has been registered at Chinese Clinical Trial Registry. Informed consent will be obtained from each involved patient and/or their designated representative. Final results from this trial will be promulgated through publications. Any protocol modification will be authorised by the ethics committee of West China Hospital and then renewed on the Chinese Clinical Trial Registry.

Ethics statements

Patient consent for publication

Not applicable.